Hearing loss is not uncommon in persons, who are either born with a hearing loss or who develop a hearing loss later in life. When a hearing loss develops, the hearing loss is not always equal bilaterally. In particular, it is not unusual that one ear will have less hearing loss than the other, and therefore have better auditory acuity than the relatively more hearing impaired other ear. For example, someone may have a 70% hearing loss in their left ear, but only a 30% hearing loss in their right ear.
Also, unusual cases exist where a tumor has destroyed or damaged one ear, although the person has an undamaged, normal opposite ear which results in an asymmetric auditory acuity between the two ears. In certain instances, the hearing loss in one ear can be very profound, so that the person for example, has an auditory acuity in a bad ear that may be only 10% to 20% of the auditory acuity of a “normal ear.”
For the sake of consistency, the application will assume that the patient's first or left ear is her “bad” ear and that the person's second right ear is her “good” ear. It will be appreciated that the choice of “first and left” for the bad ear is and “right and second” for the good ear is a purely arbitrary convention, and is not to be taken as any sort of limitation. It will also be noted that as used herein, a “good” ear is one with a greater auditory acuity than the “bad” ear, and that “good” and “bad” are relative and comparative terms, and not absolutes. It will further be appreciated that the difference between the auditory acuity of the good ear and the bad ear is highly variable between a condition where the difference in auditory acuity between the two ears is unnoticeable to the user; and an opposite extreme where the good ear has normal or above normal auditory acuity, and the bad ear has no auditory acuity. Normally an asymmetric hearing loss is treated when a person obtains hearing aids, and the asymmetric hearing loss is diagnosed by the practitioner.
The usual manner in which an asymmetric hearing loss is treated is to place a hearing aid in each of the ears. Often, the hearing aid placed in the “bad” ear can be adjusted so that it amplifies the sound to a greater degree than the hearing aid placed in the “good” ear. Unfortunately, some hearing losses are so profound that a normal or approximately symmetric hearing condition cannot be restored even with an amplification adjusted hearing aid. For example, even with a hearing aid, a patient may have an effective hearing acuity of only thirty percent (30%) in his bad ear whereas his good ear has a corrected hearing ability to within normal limits.
Patients experience difficulty with hearing in such cases where the ears cannot be corrected equally to provide symmetric hearing. In particular, a patient often will hear accurate, clear sound information out of her good ear, but garbled information out of her bad ear. This combination of garbled and clear sound information becomes very distracting to the user. In many cases, the user will treat the distraction by removing the hearing aid from the bad ear, and rely solely on the good ear to provide all of her hearing, as this is more pleasing aesthetically and is less distracting than having his hearing aid in her bad ear providing garbled sound information.
However, using only a single hearing air has drawbacks. In particular, the patient loses the sense of directionality that he obtains from having bilateral hearing. For example, if the user hears everything from his right ear and has no hearing out of this left ear, he cannot easily determine the direction from which a particular sound originates.
A further problem experienced by the user is that they are often unable to bear sounds that originate from the side of the user on which the bad ear is located. As such, a user sitting at a table might be able to very easily understand a conversation spoken by people sitting on his good ear side, but may not be able to hearing anything from those sitting on his bad ear side. This inability to hear well on one side forces the user to turn her head on a frequent basis so that her good ear is better positioned to pick up the sound originating from the side on which the bad ear is placed. This frequent head turning can also be dangerous when driving a motor vehicle, or awkward such as when trying to write notes and turning ones head often to be sure that you have heard the auditory information on which the notes are being taken.
Those with asymmetric hearing loss often try to find ways of compensating for their inability to hear well on one side. For example, persons having hearing in only one ear will often try to choose a place at a table where all of the other people at the table are seated on their “good ear side”. Another compensation technique is for the user to sit at the end of the table facing all the other persons, so that the “bad ear side” is positioned so that no one is sitting directly on the bad ear side.
Known technological fixes exist for aiding in overcoming these issues. These methods include the use of “CROS” hearing aids, “BICROS” hearing aids, and bone-anchored hearing aids.
A CROS hearing aid is a type of hearing aid that is used to treat unilateral hearing loss. A CROS hearing aid takes sound from the patient's bad ear side and transmits the sound to the good ear with better hearing. Many systems use a wireless transmitter to transmit electrical signals from the bad ear hearing aid to the good ear hearing aid.
BAHA and Trans-cranial CROS systems use the conductivity of the skull to transmit sounds. See, e.g. Wikipedia, CROS Hearing Aid, https:/en.wikipedia,org/wiki/CROS_hearing-aid; See also Myrthe K. S. Hol; Sylvia J. W. Kunst et al, “Pilot Study on the Effectiveness of the Conventional CROS, the Transcranial CROSS and the BAHA Transcranial CROS in Adults with Unilateral Inner Ear Deafness”, European Archives of Oto-Rhino-Laryngology, 2010, June 267(6), 889-896 (2009, Nov. 11).
A BICROS hearing aid system is primarily employed on patients who have little or no hearing on one side, with some hearing loss in their good ear. A BICROS system works similarly to a CROS system, except that the device on the good side is usually a fully capable hearing aid for receiving and amplifying sounds on the good ear side and is also capable of receiving the sound transmitted from the CROS hearing aid on the bad side.
BAHA (Bone Anchored Hearing Aid) is a hearing aid that is placed on the side of the bad ear, and transfers sound through bone conduction and stimulates the cochlea of the good ear. This system is designed to transmit sound from the bad side to the good hearing side to result in a sensation of hearing from the deaf ear. See umm.edu/PROGRAMS/HEARING/SERVICES/BONE-ANCHORED-DEVICE#UNILATERAL, University of Maryland Medical Center.
A BAHA hearing aid typically employs a biocompatible screw that is affixed into the skull behind the bad ear. The screw top is a coupling intended for a vibrating bone conductor hearing aid. The hearing aid vibrations are transmitted through the screw and into the skull bone and are transmitted through the skull to the opposite good ear. This is similar to a tuning fork placed on a bone so that the vibrations from the tuning fork vibrate the surfaces it touches and thereby transmits sound vibrations through the skull and to the ear.
The CROS, BICROS hearing aid and the Bone Anchored Hearing Aid provide significant advantages to the user, as they enable the user to hear information from both sides of his head. However, although they provide the hearing information to the user, known CROS, BICROS and BAHA hearing aids are not very effective in providing the patient with a sense of directionality. In essence, the user is hearing the information in “monoraul”, and does not enjoy the stereophonic sound that a person with two normally functioning ears enjoys. Because of this monoraul hearing, the user can hear the information, but cannot determine whether the sounds that he is hearing are originating from his bad hearing side or good hearing side.
Therefore, one object of the present invention is to provide a device that enables the user to have better directionality as to the source of sounds and speakers voices.